These temperature controls are designed to cover a broad range of uses for heating and general purpose requirements. Controls have SPST contacts which open on temperature increase or they may be supplied in single-pole, double-throw contact action. Various control ranges are available to cover working temperatures from -30 to 550° F (-34 to 288° C). Closed tank fittings and bulb wells are available for immersion applications. These controls are designed for open low and open high applications. Where critical or high value products are to be maintained within a specific temperature differential, a single control should not be applied to function as both an open low and open high control. In these applications, a separate backup control with alarm contacts should be wired toindicate when the back-up control operates.

The Series A19 is a small, compact control with adjustable or fixed differential. Controls supplied with adjustable differential have an internal scale plate indicating increments of differential. The controls are supplied with adjusting lever at minimum differential stamped on the control. To adjust move the lever to the differential required. Models are available with or without external range adjustment and visible scale. External range adjustment may be by screwdriver slotor range adjusting knob. A built-in high cutout stop is an integral part of these controls and may be adjusted quickly and easily in thefield.